2 years late,but just in case others are scrolling through.
This is what I do to remove the extra padding caused by the scroll bar from scroll box widgets.
If you have the default setting for a scroll box then use the following:
The way did it was to place your scroll box into a size box, which adds padding capabilities to the scroll box. Go to the Padding as below and set it to a negative value for Left. With default settings (Bar width etc) -15 works for me. Adjust the left padding to suit your scroll bar size more precisely.
